Simulation Study On Contact Mechanics And Wear Of Artificial Knee Joint

The life span of knee prosthesis depends on the wear properties,stress distribution area and contact stress of the prosthesis in relative motion are the main factors affected wear.Once the prosthesis of knee joint fails,it is necessary to repair the artificial joint for patients,which is expensive in time and money for patients and challenging for surgeons.In the clinical practice of knee arthroplasty,it is found that the stress distribution area and contact stress between the components of the artificial knee have an inseparable relationship with the flexion axis of the femoral component in the artificial knee.The influence of flexion axis on the contact stress and contact area of knee joint was studied by using Abaqus software.In total knee arthroplasty,the wear of UHMWPE tibial flat is a key factor affecting the service life of knee prosthesis.It is difficult to observe and study the wear of artificial joint materials in human body,this paper chooses pin and metal disk model to mimic artificial joint daily exercise by multiple direction relative motion.The finite element model of pin-plate was established by using Abaqus software.Pyhton was used to extract the contact stress,node coordinates and Matlab to calculate the wear parameters of pin.The effect of cross shear ratio on wear was studied.In this paper,the knee joint models of the distal and posterior fitted flexion axis and anterior and distal flexion axis are established.The distal end fitting flexion axis produces a femoral rollback effect compared with the distal end fitting flexion axis,which increases the range of flexion activity.The position of the flexion axis may affect the performance of the knee joint,which provides a theoretical basis for the doctor to install the femoral component,so as to avoid the reduction of the range of motion after knee surgery.In addition,in this paper,through the establishment of pin-plate models under different input conditions,it is found that as the rotation angle of the pin increases,the wear factor,wear cofficient,and depth of wear of the pin greatly increase,so the cross-shear effect has an important effect on UHMWPE wear.It provides calculation methods and theoretical guidance for the study of simulated wear of joint materials.